JPS5980123A - Quick charger - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to battery charging equipment, and more particularly to a rapid charging device for sealed nickel-cadmium batteries.

In recent years, portable electronic devices have been widely used, and along with this, the sealed nickel-cadmium batteries used as power sources are also large capacity M (for example, IQAH).

8AH) is used.

Therefore, there is a strong demand for a lightweight and compact quick charging device that can charge these batteries in a short time.

However, in the case of overcharging during rapid charging, the charging current is much larger than the rated charging current (10 hour rate current), so the generation of oxygen gas from the anode at the end of charging exceeds the absorption reaction at the cathode. As a result, phenomena such as an increase in internal pressure of the battery, damage to the battery, and leakage of electrolyte occur, resulting in a significant deterioration of battery characteristics and battery life.

In order to avoid this overcharging, an operation of detecting the end of charging is performed. For example, there are the following three methods.

The first method is to measure the voltage of the battery being charged. However, in this case, the terminal voltage of the battery fluctuates depending on the battery temperature, so even if temperature compensation is performed, the terminal voltage cannot necessarily be measured accurately, and as a result, over- and under-charging cannot be completely resolved. It was difficult to do so. The second method is to detect the end of charging by measuring the battery temperature at the end of charging. However, in this case, the rise in battery temperature during charging fluctuates depending on changes in room temperature, so it is necessary to detect the temperature difference between the battery and room temperature, making the charging circuit complicated and difficult to detect the complete end of charging. I can't. The third method is to attach a third electrode to the battery to be charged, and detect a sudden rise in voltage between the battery and the cathode due to gas generated at the end of charging. However, even in this case, it has been difficult to completely prevent over- and under-charging because the charging efficiency and the like of the battery are temperature-dependent.

Furthermore, the power source of conventionally used charging devices is mainly commercial alternating current that is stepped down and then rectified by a transformer, and also uses the amplification characteristics of power transistors to provide constant current charging characteristics. It is something. Therefore, when charging large capacity (10AH, 8AH, etc.) batteries, the charging device becomes large and its charging efficiency is low.
It was impossible to make it portable.

For example, a quick charging device for a 24V, 8AH battery weighs more than 20cm.

In addition, with conventional charging devices, when charging batteries of various capacities with one charging device, it is necessary to switch the charging current according to the battery capacity, and the operation is complicated, leading to malfunction. This often resulted in damage to the battery.

The present invention aims to eliminate the above-mentioned considerations in quick charging, and to provide a quick charging device that is lightweight, compact, highly portable, and can automatically perform quick charging without excess or deficiency. .

The device of the present invention attaches a third electrode to the battery to be charged, and detects the voltage between the third electrode and the battery cathode during rapid charging, and this detected voltage indicates that the battery has reached 80 to 90% charge. At that point, the device automatically switches from quick charging to normal charging and charges the remaining battery to complete charging. In the device of the present invention, a DC-DC converter, a so-called switching regulator, which is lightweight, compact, and easy to control start/stop and constant current output characteristics, is used as a charging power source, and the control circuit is computerized. It has achieved advanced functions and ease of operation.

The device of the present invention includes: a) a switching regulator that supplies a constant current for battery charging; b) a control circuit that sets the constant current characteristics of the switching regulator; and a battery capacity detection terminal provided on a C9 battery. a current value switching circuit for transmitting a desired current setting signal to the control circuit; d. a current value switching circuit connected to a third electrode provided on the battery;
, an operational amplifier that detects and amplifies the difference between an indicated voltage of a pole and a set value voltage, and when the indicated voltage exceeds the set value voltage, the relay interposed between the switching regulator and the switching regulator is dropped. an operational amplifier that terminates rapid charging, sends an activation signal to the current value switching circuit to transition to normal charging, and sends a startup signal to a subsequent timer; e. a timer that is activated in response to the signal and operates for a predetermined period of time; or a relay that stops.

The device of the present invention is shown below with a 24V output (20 unit batteries).
An example in which 8A I (, 6A H, 3,5A H) can be charged will be explained based on the drawings. Fig. 1 is a wiring diagram of a battery case to be charged using the device of the present invention, and Fig. 2 3 is a block diagram showing the connection relationship of each element of the device of the present invention, and FIG. 3 shows a specific embodiment of the device of the present invention.

In FIG. 1, E-E10 and E12-E20 are batteries to be charged, and E1 is a special battery equipped with a third electrode Eo, and its charging and discharging characteristics are the same as the 19 batteries described above. The difference in voltage between the third electrode E□ and the battery to be charged is read as a voltage value between the terminals v+ and v-.

1 is a thermostat, which is set to detect when the battery temperature becomes too high during charging; in the case shown, it is set to open at 55°C, and the signal is extracted from terminal t. Reference numeral 2 denotes a connector which is provided with the above-described v+ and v1 terminals in addition to the + and one terminals at both ends, as well as battery capacity detection terminals AH1 and AH2. When charging at 8AH with these AH terminals, it will reach.

AH2 is both open (state shown), AH1 is connected when charging 6AH, AH2 is open, 3.5
During AH charging, AH1 is left open and AH2 is connected.

In Figure 2, 3 represents the power transistor (20k).
(ON -OF"F' t at z, is a switching regulator that generates a constant current for battery charging via a high frequency transformer and a diode. Its ten terminal is connected via a diode 4 to prevent reverse current before charging starts. The switching regulator 3 is connected to a power supply via a well-known rectifier circuit 1' consisting of a rectifier and a capacitor.

Reference numeral 6 denotes a control circuit energized by an auxiliary power source 7 and provided with a current detection resistor 8. The control circuit 6 mainly consists of an operational amplifier and an oscillator, and excites the switching regulator 3 to generate its constant current characteristics.

Reference numeral 9 denotes a current value switching circuit that sends a current setting signal to the control circuit 6, which mainly outputs a signal from an inverter connected to the AH terminal of the battery case 5, and a signal from the inverter together with an operational amplifier output signal from 10, which will be described later. and a decoder that converts the signal into a current setting signal. That is, A) The battery capacity l is identified by the signal from the first terminal, and a current setting value corresponding to the capacity is generated, and a current setting value for quick charging or normal charging is generated depending on the operating state of the operational amplifier.

10 is an operational amplifier connected to the v'' and v1 terminals of the battery case, and operates by detecting the difference between the voltage indicated by the third electrode EO and a preset set value voltage.

This set value voltage is the voltage exhibited by the third electrode when the battery is 80-90% charged. When the indicated voltage of the third electrode exceeds the set value voltage, the relay 11 interposed between the operational amplifier 10 and the switchboard regulator 3 is tripped, and then an activation signal is sent to the switching circuit 9. The current setting value is switched from quick charging to normal charging, and at the same time, a start signal is sent to the timer 12 to start it and convert charging to normal charging.

13 is a signal from the timer 12 and/or t of the battery case 5;
This is a starting relay that opens and closes depending on the signal from the terminal.
℃ and the thermostat 1 becomes open, it has the function of tripping and opening the control circuit to stop the switching regulator and terminate charging.

The device of the present invention and its operation will be explained in more detail with reference to FIG. In the figure, the rectifier circuit 1' of Fig. 2, the auxiliary power supply 7,
The battery cylinder 5 is omitted. First, a child terminal of the switching regulator 3 is connected to a child terminal of the battery cylinder via a backflow prevention diode 4, and one terminal is connected to the battery cylinder one terminal.

Power transistor 3' of switching regulator 3
is oscillated by the control circuit 6, and the output power is changed by changing the ratio of the ON-OFF width. The control circuit 6 is configured as an integrated circuit, and its AMP section 6' includes a current detection resistor 8.
The voltage dropped by and the potential at point A are the resistance R,13,
The potential divided by R14 and P-type 5 is compared and amplified to generate constant current characteristics of the switching regulator 3. In this case, the current value can be controlled by controlling the potential at point A, which is done by controlling the potential at the input terminal of the voltage follower operational amplifier 9' connected in the switching circuit 9. It becomes possible.

The switching circuit 9 is an inverter 9 connected to AHI and AH2.
“Input the binary power from this inverter 9 to terminal a,
Receive at b, decimal output terminal 0°1.2. ...9
A decoder 9″′ that sets any one of them to 0′ V (L signal)
and a voltage 7 lower operational amplifier 9' connected to each output terminal via a resistor. Further, a signal is inputted to a terminal C of this switching circuit 9 from an operational amplifier 10, which will be described later.

Reference numeral 10 denotes an operational amplifier connected to the terminals v" and v-, which compares and amplifies the voltage with a set voltage determined by a resistor R1, a Zener diode D2, and a variable resistor (2).

■When + is lower than the set value voltage, the output signal is -
It transmits 0V (L signal) and drives the relay 11, but as charging progresses and V+ rises and exceeds the set voltage,
As relay 11 is dropped, its output signal rises to H.
A signal (15■ in the figure) is transmitted through R4, the input terminal d of the decoder 9'' is set to I (state), and as described later, the switching circuit 9 is activated to transmit a current setting signal and charge normally. At the same time, the H signal of the operational amplifier 10 starts the timer 12, and the -
Allow normal charging to proceed in between.

When normal charging progresses and a predetermined time has elapsed, the relay 13 is tripped by the operation of the timer 12, the control circuit 6 is stopped, the switching regulator 3 is stopped, and the overall charging is completed. If the temperature of the battery rises excessively during charging and reaches 55° C. or higher, the thermostat opens and drops the relay 13 to stop charging and prevent damage to the battery.

The switching circuit 9 operates as follows. For example, in the case of 8A H charging, during rapid charging terminals AH1, AH2° resistor R2,
The circuit of R13 causes the H signal to be input to the input terminal of inverter g/A□, and therefore the input terminal a of decoder 9'''
, b, and c are input with an L signal.

That is, since the input signal is 000 in binary, the output terminal 0 of the decoder 9''' is in the L state, and only the resistor R97 is inserted, and the voltage divided with R16 is supplied to the operational amplifier 9' for the voltage follower. Therefore, the potential at point A shows a predetermined value.As a result, at that potential, the control circuit 6 gives an instruction of constant current characteristics to the switching regulator 3, and the current necessary for rapid charging is supplied to the battery.

Similarly, in the case of 6AH charging, the input signals at the input terminals a, b, and c of the decoder 9'' are 001, so the output terminal 1 becomes the L state and the resistor R8 is inserted to set the necessary current. The switching regulator 3 supplies the value.In the case of 3.5 AH charging, the input signal of the decoder 9/17 is 010, so its output terminal 2 is in the L state and the resistor R9 is inserted.

As mentioned above, when + exceeds the set value type pressure, the operational amplifier 10 trips the relay 11, activates the tie T12, and sends an activation signal to the switching circuit 9 to switch to normal charging. In this case, the input terminal a of the decoder 9''
Since the input signal changes to b and c by 100°101.110, output terminals 4 and 5.6 are in the L state, respectively, and one of resistors B, IO, R11, and R12 is inserted, and the corresponding The potential at point A changes. At this time, since relay Ry is off, resistor R15 is inserted and RI
Together with OI R111R12, the necessary charging current will be obtained.

In this way, the device of the present invention operates the starting relay 13 and controls the switching regulator 3 via the control circuit 6.
, and start rapid charging with a predetermined current.

This rapid charging continues with constant current characteristics until the indicated voltage (V+) of the third lightning pole becomes equal to or higher than the set value voltage, and as charging progresses and V+ increases and becomes equal to or higher than the set value voltage, the operational amplifier 10 automatically switches to normal charging, and after the timer 12 starts and a predetermined time elapses, the start relay 1
3 falls and charging ends.

In the device of the present invention, quick charging is usually performed at a one hour rate (
IC) for 45-50 minutes, then normal charging at a rate of 10 hours (
The charging time can be significantly shortened by approximately 150 minutes for the battery (N, IC). In particular, it is clear that the rapid charging time is shortened when charging a battery that is in the middle of discharging. Also, even if you discharge immediately after quick charging is completed, the discharge capacity will be 8.
It is 0 to 90%, which is a large amount in practical use.

Furthermore, in the device of the present invention, easily available and highly reliable integrated circuits can be used for the switching regulator control circuit, decoder, inverter, timer, operational amplifier, etc., and the device is lightweight and compact. It is highly portable.

In the device of the present invention, the set voltage is 80% to 90%
This is the voltage of the battery when it is charged.

In other words, the device of the present invention rapidly charges to this voltage, and when the battery is charged to that point, automatically switches to normal charging.
Charging is completed without overcharging.

For example, the results of charging and discharging the device of the present invention shown in FIG. 3 are shown in the table in comparison with the conventional method.

As is clear from the table, the device of the present invention can charge up to 80
It can be charged to ~90%, and a full charge can be achieved with an additional 150 minutes of normal charging. Therefore, charging time can be significantly shortened. Moreover, the rapidly charged battery can be directly used for discharging if necessary. Furthermore, it is lightweight (approximately 4#) and small, making it highly portable. Furthermore, since all charging can be done automatically, its industrial value is extremely large.

[Brief explanation of the drawing]

Fig. 1 is a wiring diagram of a battery cylinder to which the device of the present invention is connected, Fig. 2 is a block diagram showing the connection relationship of each element of the device of the present invention, and Fig. 3 is a specific example of the device of the present invention. be. 1...Thermostat, 2...Connector, 3...
, switching regulator, 4, backflow prevention diode, 5... battery cylinder, 6... control circuit, 7...
, vJ auxiliary power supply 8...current detection resistor, 99. , current value switching circuit, 10... operational amplifier, 116. Relay, 12, Timer, 13...Start relay.

Claims (1)

[Claims] 1. a. A switching regulator that supplies a constant current for battery charging; b. A control circuit that sets constant current characteristics of the switching regulator; and a connection to a battery capacity detection terminal provided in the C1 battery. d) a current value switching circuit for transmitting a desired current setting signal to the control circuit; The arithmetic intensifier detects and amplifies the current value by dropping the relay interposed between the switching regulator and the switching regulator when the indicated π voltage becomes equal to or higher than the set value voltage. an operational amplifier that sends an activation signal to the switching circuit to transition to normal charging and also sends a activation signal to a subsequent timer; e. a timer that is activated upon receiving the activation signal from the operational amplifier and operates for a predetermined period of time; and f, a relay that opens and closes in response to a signal from the timer or a signal from a battery temperature detection thermostat included in the battery, and starts or stops the switching regulator via the control circuit. A quick charging device. 2. The quick charging device according to claim 1, wherein the set value lightning 1 voltage to be compared with the third M-pole indicated voltage is a voltage at 80 to 90% charging.